Conventionally, there is known a valve timing control apparatus including a restricting mechanism which is provided separately from a locking mechanism for locking a relative rotational phase of a driven-side rotary member relative to a driving-side rotary member to a predetermined phase (locked phase), the restricting mechanism being constituted of a restricting recess formed in the driven-side rotary member and a restricting member provided in the driving-side rotary member and projectable/retractable into/from the restricting recess.
For instance, a restricting mechanism is known from PTL 1 which consists of an engaging pin 91 (“a restricting member”) and an engaging groove 28 (“a restricting recess”). With this arrangement, it is possible to first restrict the relative rotational phase of the driven-side rotary member relative to the driving-side rotary member to a predetermined range and then to allow the locking mechanism to be actuated. Hence, there is provided the advantage of the locked state being realized more easily.
Further, the valve timing control apparatus disclosed in PTL 1 adopts the arrangement wherein an amount of fluid is discharged from an advance angle chamber and a retard angle chamber when the relative rotational phase is not the locked phase at the time of engine start. This arrangement is provided for realizing the locked state when and while the driven-side rotary member is rendered positively rotatable relative to the driving-side rotary member immediately after engine start.